DE7526604U - Electric disconnector for AC power lines - Google Patents

Description

Jean-Louis GRATZMULLER, Neuilly sur Seine / France

Electric disconnector for AC power lines

The invention relates to an electrical circuit breaker for alternating current lines with a fixed and the ■ movable contact for opening and closing the switch and with a _{liquid dielectric especially formed by a liquefied gas such as SF ß} filled separating chamber in which the gas is constantly under a substantially constant pressure is maintained.

Sulfur hexafluoride (SF ₆ ), which is in gaseous form, has proven itself very well as a dielectric for such disconnectors in the pressure-liquefied state.

Among the disconnectors of this type, the invention relates specifically to those in which the movable X Contact with pressure under the action of a push actuator

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transmission organ is applied to the fixed contact in the closed position of the switch and in which the moving contact of , an axial channel is penetrated, which is a spark extinguishing

_{t forms} nozzle for the liquid dielectric and opens in the vicinity of the contacts in the area between the contacts. In such switches, the spark extinction is brought about at the moment the contacts are opened by an intense centripetal flow of the liquid dielectric flowing out of the separating chamber.

Disconnectors of this type are in particular from French patents 1 430 333, 1 537 673 and 2 154 928 known.

The object of the invention is to provide an improved, and in particular a temporal, circuit breaker of this type to achieve extended spark quenching for effective interruption of the alternating current.

In these known disconnectors, the spark extinction only works during the period of the removal of the movable contact, which is very short in such disconnectors, for example in the order of 1 to 3 milliseconds, since, with regard to the dielectric quality of SF ₆ in the liquid state, the The distance between the contacts in the open position can be very small, for example on the order of 10 millimeters for a voltage of 200 kilovolts. Such a spark quenching works very well with circuit breakers for direct current.

In the event of an interruption in alternating current, for example from industrial frequencies or higher frequencies, the Spark is only extinguished when the current crosses zero

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v / earth, so that the spark extinction after reaching the open position of the movable contact can be extended,

must to safely extinguish the spark. ι

With the present invention, an ultra-fast opening circuit breaker is now provided, but in which the The spark extinguishing process is sufficiently extended to safely extinguish the spark arc even with alternating current, at the same time the contacts are cooled and the liquid dielectric is completely deionized.

In the case of an electrical circuit breaker for alternating current lines with a _{separating chamber that surrounds the fixed and movable contacts and is filled with a liquid dielectric formed in particular by a pressure-liquefied gas such as SF fi} , in which the movable contact is pushed into the fixed contact solely by an axial pressure force the closed position of the circuit breaker is pressed under the influence of a thrust actuator and in which the movable contact is penetrated by an axial channel which forms a spark extinguishing nozzle through which the liquid dielectric flows centripetally »which opens in the vicinity of the contacts and between them, thereby released, that the movable contact is provided on a first piston which cooperates with a coaxially arranged second piston, the spark extinguishing piston, wherein the two pistons are slidably mounted in one another and are slidable as a whole in a bore which the The bottom of the separation chamber penetrates so that each of the two pistons has a surface acted upon by the pressure-liquefied dielectric in the separation chamber, that the assembly consisting of the two pistons can be controlled by the thrust drive and that stops the stroke of the first piston to a value smaller than that of the second piston so that the spark

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extinguishing is extended for a period of time that begins at the moment when the bearing on the first piston moving contact its maximum distance from the fixed

, Has reached contact.

In a preferred development of the invention, the first piston, which carries the movable contact, is an annular piston designed like a hollow cylinder that slides in the bore, the second piston is designed as a full piston, which slides inside the first piston and between one of its working surfaces and that of the movable contact opposite surface forms an auxiliary extinguishing chamber with variable volume, which is connected to the separation chamber the channel is in communication, and the thrust drive acts on the second piston.

This ensures that the drive, for example the piston rod of a hydraulic control cylinder, during a part of its path of movement can perform relative movements with respect to the movable contact that so when the circuit breaker is opened, the extinguishing piston can continue to move in the extinguishing cylinder after the movable one Contact has reached its end position at a distance from the fixed contact, so that the volume of the auxiliary arcing chamber is enlarged and so an intensive circulation in the extinguishing nozzle for a sufficient period of time of the liquid dielectric is achieved from the separation chamber. As will be explained in more detail below, is the drive during part of its path of movement with respect to the closing of the disconnector movable contact relatively movable.

According to another development of the invention, the two pistons are mirror images of each other, whereby

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not just an extension of the spark extinction

after reaching the maximum distance of the movable contact, but also in a preferred development of the invention, an onset of spark extinction is already achieved when the movable contact begins to move away from solid contact.

According to this embodiment of the invention is the second Piston, the extinguishing piston, an annular piston, inside which the first piston with the movable contact slides. Through this an auxiliary extinguishing chamber is created, the volume of which is already at the beginning of the movement of the two Piston and the movable contact assembly formed changes in the direction of increasing the spacing of the contacts.

The invention is just as applicable to such circuit breakers in which the opening movement of the movable Contact is positively generated by a linear actuator or the like, as is the case with such disconnectors where, as always possible, an elastic switching drive (for example a gas spring) is used, which is the case with Releasing the drive links removes the movable contact from the fixed contact, as well as eventually with such Disconnectors in which such elastic switching elements formed exclusively by the volume elasticity of the liquid dielectric SF, which is in the separation chamber and which seeks to push away the movable contact, as in the case of the ones mentioned above known disconnectors is the case.

Further details, features and advantages of the invention emerge from the following description of exemplary embodiments based on the drawing, in particular in connection with the additional claims.

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ι ₍ It shows

, Fig. 1 is a section through a separation according to the invention

_t switch in its closed position,

FIG. 2 shows a partial section through the switch according to FIG. 1

in its open position,

3 shows a partial section through another embodiment of the switch according to the invention in its open position in a representation according to FIG. 2,

4 to 6 partial sections through a further embodiment of a switch according to the invention in the closed position, during the opening movement and in the open position.

The circuit breaker illustrated in FIG. 1 has a housing body 2, preferably made of metal, in the interior of which a separating chamber 4 is worked. The separating chamber 4 encloses a fixed contact 6 and a movable contact S. The fixed contact 6 is connected to one of the terminals 10 of the circuit breaker by an electrically conductive connecting rod 12 which is surrounded by insulating tubes 14-14 '. The movable contact 8 is electrically connected to the other terminal 16 of the circuit breaker by a sliding cylinder 18 and a metal braid 20, as will be explained in detail below.

The separating chamber 4 is filled with liquefied SF ^, which is constantly below a pressure that is considerably above the critical pressure (36, bat or 36.1 liar for SFg), for example 2- to 10-fi-i ^ hen.-Μ ^ ς ^ _ς Dv-urkr ^, nchalten, this pressure being maintained by suitable means that are explained in the publications mentioned in the introduction and are not shown in more detail. j

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f '

ΐ ■:

ί.

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, First, an embodiment will be explained in which the:

\ , Volume elasticity of the liquefied SF _ß for generation -

the switching movement of the switch to the open position

j is used; in this case the pressure of the dielectric;

cumulative in the order of magnitude of 200 to 400 bar can be selected] the. ;

f The movable contact 8 is provided with an axial channel 22

y provided and attached to the hollow cylinder 18, which is tight in

a bore 23 in the bottom 24 of the housing body 2 of the Disconnector can slide.

In the interior of the cylinder 18, a piston 26 can also slide tightly, which in the present example is driven by the piston rod 28 of a hydraulic control cylinder 30 formed drive.

In the closed position of the disconnector, which is shown in FIG. 1, the movable contact 8 rests against the fixed contact 6 under pressure. The contact pressure is maintained by the hydraulic control pressure in the control cylinder 30 and transmitted to the movable contact 8 by means of the piston rod 28, which forms a thrust drive, and the extinguishing piston 26, which in this position rests against the inner surface of the movable contact. As in the fixed contact 6, the movable contact 8 is _{pressed against the volumetric elasticity of the liquid SF 6} contained in the separating chamber 4, the elasticity of the SF ₆ trying to push the movable contact out of the separating chamber. '

The top of the quenching piston 26 forms with the bottom of the movable contact 8 an auxiliary quenching chamber 32, '·: with the interior of the separation chamber 4 only via the; axial channel 22 in the movable contact 8 is in communication.

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/ By means of a hydraulic control system 32, which in f

<Figs. 1 and 2 is shown only by way of example, is , the transfer of the disconnector to the open position

, achieved in that the hydraulic control cylinder 30

is relieved of pressure, for which purpose a control valve 36 is transferred to its open position shown in FIG.

As soon as the pressure oil contained in the hydraulic control cylinder 30 is relieved of pressure, the pressure force disappears of the movable contact 8 and that of the movable contact 8, the cylinder 18 and the piston 26 moves existing assembly without relative changes in the position of their components to each other under the influence of the pressure of the SF, -

ι on the annular surface of the movable contact 8 and on

<the surface of the extinguishing piston 26 downwards.

The moving contact thus moves away from the fixed contact until it reaches its maximum distance, the through suitable stops is defined, for example by a stop on the lower edge 38 of the cylinder 18 a pressure surface 40 in the lower region of the housing body 2, as is illustrated in FIG. 2.

During this first section of the opening of the switch, the liquid SFg fills under the influence of its volumetric Elasticity removes the space between the two contacts and essentially centers the arc in the axis of the contacts.

The pressure of the SF, - continues to act on the upper surface of the

Piston 26, which is pressed further downwards and in the process ■ pushes back the piston of control cylinder 30, ^f via piston rod. 28, from which hydraulic fluid flows via open valve 36 into a low-pressure accumulator 42.

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t ic t · · ■ *

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I ■ 4 I «f
«Tt
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During this second section of the opening of the circuit breaker, the piston 26 thus moves separately from the movable contact 8 and from the extinguishing cylinder 18, the

Volume of the quenching chamber 32 grows and a strong ι

Centripetal flow according to arrows 44 in FIG. 2 between the separation chamber 4 and the quenching chamber 32 is set. The opposite surfaces of the two contacts together with the axial channel 22 form a nozzle-like passage through which the liquid dielectric material is conducted and thereby subjects the arc to strong turbulence and high-energy extinction. The deletion can therefore take place for a sufficient period of time after the end distance between the two contacts has been reached can be extended, whereby the spark arc is extinguished at the next zero crossing of the current.

The components can be arranged and driven in such a way that the second section of the switch opening (deletion) sirh over a period of time of, for example, three to six times the duration of the first switching section (mutual distance of contacts) extends.

In order to close the circuit breaker again, the hydraulic control pressure is introduced into the cylinder 30, for which after closing the valve 36 a known, not shown device is provided so that the Löschkoiben 26 moves up again against the underside of the movable Contact and this again applies against the fixed contact, this closing process taking place against the volumetric elasticity of the SF _g in the separation chamber 4.

In the embodiment just explained, only the volumetric elasticity of the liquid SF ₆ serves as a spring drive for the transfer of the disconnector to the open

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, 3, ti *

Ii 'riliti ·!

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Position. In one with dashed lines in FIG. 1

As shown in the modification, a hydraulic accumulator 46, for example a hydro-pneumatic accumulator, can be used, one section 48 of which, which is in communication with the separating chamber 4 via an unthrottled line 50 _{, is filled with SF 6} in the liquid state, while the other section 52 is filled with a compressed gas, for example with nitrogen or helium.

In a circuit breaker according to the invention, the hydraulic control can take place in any known manner, it is only essential that a quick response to the control signal is achieved. The control device 34, some of which are shown in Fiq. 1 is represented by of a design according to patent application P 25 12 4Ü0.5

In addition, it should be explained that the control device is essentially a fast-responding electric valve for Pressure relief with small flow area 54, which the opening of a succession of pressure relief valves controls with increasing cross-sections, the last of which is the valve 36 of the control cylinder 30 *

In the embodiment illustrated in FIG. 3, the movable contact 8 ¹ penetrated by the axial channel 22 is provided on a first piston 56, which is slidably mounted in the interior of a second piston 58 for extinction. In this case, the extinguishing piston 58 is an annular piston which, sealed by means of a seal 60, can slide in the bore 23 in the base 24 of the isolating chamber 4 of the isolating switch. A sealing contact between the piston 56 and the annular piston 58 is ensured by a seal 62.

The base body 64 of the movable contact 8 'is also held slidably in the bore 23, wherein a

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Ρ ι · '■ «··

11 -

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■: Seal 66 only on the base body 64 of the movable

I 'contact ensures a seal with respect to the bore 23

] 'performs. The annular surface 68 of the extinguishing piston 58 delimits

}., 'in the bore 23 with the opposite annular surface

I of the base body 64 of the movable contact an auxiliary

f arcing chamber 32 'with variable volume , which over the channel

ii is in communication with the separation chamber 4.

I There are stops on the moving contact, for example a

Jj flange-shaped collar part 72, provided that the stroke of the

I "moving contact to a value less than that

(Limit the stroke of the extinguishing piston 58, whereby the stroke of the extinguishing

I piston 58 is limited by a stop 74.

ί 'The drive of the disconnector, for example a hydraulic one.

I 'cylinder or piston 30' acts jointly during thrust

j 'both pistons 56 and 58.

The mode of operation is explained in detail below with reference to the exemplary embodiment according to FIGS. 4 to 6, it being noted that in the closed position the channel 32 'has a minimum volume. When the pressure in the cylinder 30 'is reduced, the pressure of the dielectric pushes the assembly consisting of the piston 56 and 58 downward until the path of movement of the movable contact 8 ¹ through the

\ Stop is limited, after which during a second

i ' movement section of the annular piston 58 moves alone ^ pus

I * is so that the volume of the chamber 32 is increased and one

I intense centripetal flow of the dielectric for quenching

is generated in the direction of arrows 44. The extinguishing is thus extended until the extinguishing piston 58 strikes its stop 74 .

A suction channel 76 prevents a pressure drop in the volume 78, which occurs when moving into the open position between the

Piston is generated. Sliding contacts or a flexible \\

Litz wire secure the passage of current in a manner not shown from the movable contact to the bottom 24 of the separation chamber and to the output terminal of the circuit breaker.

In the embodiment just described, the deletion takes place over an extended period of time, but does not begin until the movable contact 8 ^{1 has reached} its end position in the open position of the disconnector.

An embodiment will now be made with reference to FIGS explains, in which the deletion begins as soon as the moving contact moves away from the fixed contact begins and at which the deletion continues beyond the moment at which the moving contact is his Has reached the end position in the open position of the disconnector.

In this embodiment too, the extinguishing piston 58 is a Ring piston that is sealed in the bore. 23 'slides in the floor 24. The contact 8 ″ is fixed to the first piston 56 connected, which is kept slidably sealed inside the extinguishing piston.

In this embodiment, however, the bore 23 ' a section of large diameter, which receives the annular piston 58, and a second section 23 "smaller Diameter, which receives an intermediate piece 64 *, which connects the movable contact 8 ″ with the first piston 56.

In the embodiment according to FIGS. 4 to 6, the intermediate piece 64 'of the same diameter as the piston 56 \\ on, but this diameter can be different. H

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• m js *

- 13 -

A seal 66 seals the passage of the intermediate piece 64 \ by the portion 23 · of the bore, and a sliding contact 80 ensures current transfer from the movable contact to the output terminal of the Trennsehalters on the bottom of the separation chamber 4 of time.

The intermediate piece 64 'is penetrated by a channel 82, that with the axial channel 22 of the movable contact and with the quenching chamber 32 'with variable volume in connection stands (see. Fig. 5 and 6).

To simplify the construction and assembly of the disconnector, the section 23 'can have a reduced diameter the bore is not cut directly into the bottom of the separation chamber, but rather in a connecting piece be provided.

The arcing chamber 32 · with variable volume is through the upper annular surface 68 of the extinguishing piston and the opposite fixed annular surface 86 bounded, which is part of the bottom 24 is the separating chamber or part of the chock 84, if one is used.

In the closed position of the circuit breaker, which is illustrated in FIG. 4, the hydraulic drive cylinder exercises 30 'or a piston rod of this cylinder exerts pressure force on the underside of the piston 56 and thus holds the movable contact 8 ″ in contact with the fixed contact 6 against the pressure of the dielectric in the separating chamber 4. Simultaneously the drive cylinder 30 'also acts on the underside of the ring-shaped extinguishing piston 58 and holds it Piston in its uppermost position, also on this piston from the pressure of the dielectric one down directed compressive force is exerted, which through the channels 22 and 82 on its annular upper side

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te 68 acting pressure is generated.

In this position, the volume of the quenching chamber 32 'is minimal .

To move the disconnector into the open position, the drive ^{cylinder 30 1} , the piston of which presses from below against the two pistons 56 and 58 and loads them against the counterpressure of the dielectric, is relieved of pressure. During the first section of the switching movement, the two pistons 56 and 58 are pushed back together, as if they were connected, until the movable contact has reached its maximum distance from the fixed contact and the stop 72 of the fixed contact strikes the bottom of the separating channel (see Fig. 5). During this first section of the switching movement, the volume of the chamber 32 ′ increases, as a result of which the centripetal flow of the liquid dielectric, which is illustrated by the arrows 44, is already generated at the beginning of the movement of the contacts apart. This centripetal flow centers the spark arc between the two contacts so that it does not wander aimlessly in the separation chamber, as would be the case with flow and quenching in the opposite direction of flow.

In this position illustrated in FIG. 5, the movable contact is at its maximum distance from the fixed contact reached and is through the stop 7? set while the annular piston 5ö, whose set stroke is greater and which is still under the pressure of the liquid dielectric - continues to move against the drive cylinder 30 ' moved down. The volume in the chamber 32 'thus continues to grow and the extinction is thus prolonged, with a Extinguishing flow according to arrows 44 takes place until the ring

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piston 58 has reached its stroke end division, which is determined by the stop 74 (see FIG. 6), for example. *

A pressure drop in the volume 78 generated between the piston is avoided by means of suction channels 76-77.

If you want to switch to the closed position again, the hydraulic drive cylinder 30 ″ is thus put under pressure, which is only in a first switching section the extinguishing piston 58 raises again to the position shown in FIG. Slides during a second switching section the drive cylinder 30 'which consists of the two pistons 56 and 58 existing assembly upwards until the movable contact is pressed against the fixed contact again and so the circuit breaker is closed.

During this switching movement, the volume of the chamber 32 ^s decreases and the volume of liquid dielectric contained therein is pushed back into the separating chamber in a flow running approximately in the opposite direction of the arrows 44.

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Claims (7)

(New) protection claims: 1.Electric disconnector for alternating current lines with a separating chamber that surrounds the fixed and movable contacts and is filled with a liquid dielectric, in particular formed by a pressure-liquefied gas such as SFg, the movable contact of which is pressed against the fixed contact by means of a thrust drive exclusively by axial pressure in the closed position, the movable contact being penetrated by an axial channel which forms an extinguishing nozzle with centripetal flow of the liquid dielectric and opens out in the vicinity of the two contacts and between them, characterized in that the movable contact (8; 8 »; 8 ^I! ) on one first piston (18; 56) is provided which cooperates with a second extinguishing piston (26; 58) coaxial with the first piston, the two pistons in one another and the assembly formed from the two coaxial pistons in a bore (23; 23 ', 23 "). which penetrates the bottom (24) of the separation chamber (4), versc It is important to note that each of the two pistons has a separating channel containing the pressurized dielectric 7526604 03/11/76 (4) has a surface (e.g. 68) connected by a pressure medium passage, and that a stop (40; 72) for Limitation of the stroke of the first piston (18; 56) to a value less than the stroke of the second piston (26; 58) is provided. 2. Disconnector according to claim 1, characterized in that the first piston (18), which has the movable contact (8), an annular piston formed by a hollow cylinder held in a slidable manner in the bore (24) is that the second piston (26) is a full piston that is slidably mounted inside the first piston, an auxiliary arcing chamber between one of its surfaces and the opposite surface of the movable contact (8) (32) of variable volume, which is connected to the separation chamber (4) via the channel (22), and that the drive device (30) acts on the second piston. 3. Disconnector according to claim Λ _t, characterized in that the second piston (58) serving as an extinguishing piston is an annular piston slidably mounted in the bore (23; 23 '), that the first, the movable contact (8 ¹ ; 8 ¹ ') ) having piston (56) is slidably mounted inside the second piston, and that the annular surface (68) of the second piston in the bore (23; 23 ') bounds an auxiliary extinguishing chamber (32 ¹ ) of variable volume, which over the movable contact penetrating channel (22) is in communication with the separating chamber (4), the drive device (30 ¹ ) acting jointly on both pistons. 4. Disconnector according to claim 3 »characterized in that the auxiliary extinguishing chamber (32 ·) on the ring surface 7526604 11.0176 «T (68) of the second piston (58) opposite side at least partially through an annular surface (70) of the first Piston (56) or the movable contact (8 ·) is limited. 5. Disconnector according to claim 3, characterized in that the bore (23 ¹ ) has a first section of large diameter, which has the diameter of the second piston (58), and a second section (23 ¹¹ ) of smaller diameter, the auxiliary quenching chamber ( 32) on the side opposite the annular surface (68) of the second piston (58) is at least partially limited by a fixed annular surface (86) which is part of the bottom (24) of the separating chamber (4) in which the bore (23 ') is provided. 6. Disconnector according to Claim 5, characterized in that the second section (23 ««) of the bore (23 ¹ ) has the diameter of the first piston (56). 7. Disconnector according to one of claims 1 to 6, characterized in that the drive device (30; 30 ') is formed by a hydraulic cylinder, the piston rod (28) of which pressurizes one of the pistons (26; 5 &) directly. 7526604 11.0J.78